1. Field of Invention
The present invention relates to a novel quinoline(naphthyridine) carboxylic acid derivative having an excellent antibacterial activity. More specifically, the present invention relates to a novel quinoline(naphthyridine)carboxylic acid derivative represented by the following formula (I), which has an 4-aminomethyl-3-oximepyrrolidine substituent on 7-position of the quinolone nucleus and shows a superior antibacterial activity in contrast to the known quinolone antibacterial agents and also has a broad antibacterial spectrum and a highly improved pharmacokinetic property: ##STR2## and its pharmaceutically acceptable non-toxic salt, its physiologically hydrolyzable ester, solvate and isomer, in which
R represents hydrogen, methyl or amino; PA1 Q represents C--H, C--F, C--Cl, C--OH, C--CH.sub.3, C--O--CH.sub.3 or N; PA1 R.sub.1 represents cyclopropyl, ethyl, or phenyl which is substituted with one or more fluorine atom(s); PA1 R.sub.2 represents one of the following a) through e): PA1 R.sub.3 and R.sub.4 independently of one another represent hydrogen or C.sub.1 -C.sub.3 alkyl or R.sub.3 and R.sub.4 together with a nitrogen atom to which they are attached can form a ring. PA1 R' represents hydrogen or methyl; PA1 X represents C--H, C--F or N; and PA1 n denotes 1 or 2. PA1 X represents C--H, C--F or C--Cl; and PA1 R' represents oxime or hydroxyaminopyrrolidine-derived substituent. PA1 R.sub.2 represents hydrogen, amino, fluoro or hydroxy; PA1 R.sub.3 represents C.sub.3 -C.sub.7 cycloalkyl; PA1 R.sub.4 represents methoxy or fluoro; PA1 R.sub.5 and R.sub.6 can be identical with or different from each other and independently of one another represent hydrogen or alkyl, or R.sub.5 and R.sub.6 together can form C.sub.3 -C.sub.5 cycloalkyl; PA1 m denotes 0 or 1; and PA1 n denotes an integer of 1 to 3.
a) hydrogen, straight or branched C.sub.1 -C.sub.4 alkyl, cyclopropyl, cyclopropylmethyl, C.sub.3 -C.sub.6 alkynyl, 2-haloethyl, methoxymethyl, methoxycarbonylmethyl, aryl or allyl, PA2 b) a group of the following formula (1), ##STR3## wherein X represents hydrogen, 2, 3 or 4-fluoro, cyano, nitro, methoxy, C.sub.1 -C.sub.4 alkyl, or 2,4-difluoro, PA2 c) a group of the following formula (2), ##STR4## d) a heteroarylmethyl of the following formula (3), ##STR5## e) a group of the following formula (4), ##STR6## wherein n denotes 0 or 1, m denotes 0, 1 or 2, and X represents methylene, O or N, and
The present invention also relates to a process for preparing the compound of formula (I), as defined above, and an antibacterial composition comprising the compound of formula (I) as an active component.
2. Background Art
Since in 1962 nalidixic acid was first introduced as an agent for treating urinary tract infection (see, G. Y. Lesher, et al., J. Med. Chem. 5, 1063-1065 (1962)), numerous quinoline carboxylic acid antibacterial agents, including oxolinic acid, rosoxacin, pipemidic acid, etc., have been developed. However, these early-stage antibaterial agents have a little activity against gram-positive bacterial strains and thus have been used only against gram-negative strains.
Recently, norfloxacin which is the quinolone compound having a fluorine on 6-position has been newly developed (see, H. Koga, et al., J. Med. Chem., 23, 1358-1363 (1980)), and thereafter an extensive study to develop various quinolone antabacterial compounds has been conducted. However, since norfloxacin has a weak antibacterial activity against gram-positive strains and shows poor distribution and absorption in living body, it has been used only for treatment of diseases including urinary tract infections, gastro-intestinal infections, sexually transmitted diseases and the like. Thereafter, ciprofloxacin (see, R. Wise, et al., J. Antimicrob. Agents Chemother., 23, 559 (1983)), ofloxacin (see, K. Sata, et al., Antimicrob. Agents Chemother., 22, 548 (1982)) and the like have been developed. These antibacterial agents have a superior and broad antibacterial activity in comparison with the early-stage antibacterial compounds, and therefore, have been widely and practically used for treatment of diseases in clinical field.
The compounds in use or under clinical test include mainly the derivatives having a piperazine substituent on 7-position of the quinolone nucleus as in ciprofloxacin or ofloxacin. However, as a result of the study to develop quinolone compounds having a more potent and broad antibacterial activity it has been disclosed that a compound having an 3-amino or 3-aminomethylpyrroidine group introduced into 7-position has an increased activity against gram-positive strains, in comparison with the compounds having 7-piperazine group, while maintaining a potent activity against gram-negative strains. However, unfortunately, the compounds having pyrrolidine substituent have a low solubility in water in comparison with the compounds having piperazine substituent, and thus their in-vivo antibacterial activity is not so high as the in-vitro activity. Accordingly, numerous study has been continuously conducted to improve the disadvantage of the compounds having pyrrolidine substituent, that is, to increase the solubility in water and to improve the pharmacokinetic property.
As a result, many reports of such study have been made. For example, it has been disclosed that ((2S, 4S)-4-amino-2-methylpyrrolidinyl)naphthyridine derivatives (see, Rosen, T., Chu, D. T. W. etc. J. Med. Chem. 1988, 31, 1598-1611) or (trans-3-amino-4-methylpyrrolidinyl)naphthyridine derivatives (see, Matsumoto, J. et al., Proceedings of the 14th International Congress of Chemotherapy; Ishigami, J., Ed.; University of Tokyo Press: Tokyo, 1985; pp 1519-1520) shows a 20 to 40 times increase in water-solubility, an increased bioavailability and an improved pharmacokinetic property, in comparison with the compounds having no methyl group, with a similar in-vitro antibacterial activity.
In addition, an attempt to improve the disadvantage of the prior quinolone compounds including a relatively low antibacterial activity against gram-positive strains, a low water-solubility and a poor pharmacokinetic property has been made by introducing different functional groups, instead of amino group, into the pyrrolidine or piperazine moiety. As one of such attempt, some compounds having an oxime group introduced into the 7-amine moiety of quinolone compounds have been reported. For example, the researchers of Abbott have reported in a scientific journal, J. Med. Chem., 1992, 35, 1392-1398, that the quinolone compound having the following general formula A! wherein 3-oxime(or methyloxime)pyrrolidine group or 4-oxime(or methyloxime)piperidine group is substituted on 7-position of quinolone nucleus exhibits a good antibacterial activity against gram-positive strains: ##STR7## in which R represents cyclopropyl or 2,4-difluorophenyl;
The compound A! has some disadvantages that it shows a good antibacterial activity against gram-positive strains but a relatively weak activity against gram-negative strains, and also has a relatively low antibacteral activity in in-vivo test.
In addition, Japanese Laid-open Patent Publication No. (Hei) 01-100165 (1989) discloses the compound having the following general formula B!: ##STR8## in which R represents cyclopropyl, 2,4-difluorophenyl or 4-hydroxyphenyl;
Specifically, in said Japanese laid-open publication the oxime or hydroxyaminopyrrolidine-derived groups as R' substituent are very broadly disclosed. However, only the 3-hydroxyaminopyrrolidine the following formula (a)!, 3-methoxyaminopyrrolidine the following formula (b)!, 3-amino-4-methoxyaminopyrrolidine the following formula (c)!, 3-oximepyrrolidine the following formula (d)! and 3-methyloximepyrrolidine the following formula (e)! groups are specifically exemplified but the pyrrolidine substituent having both 3-oxime and 4-aminomethyl groups has never been specifically mentioned. ##STR9##
Further, European Early Patent Publication No. 0 541 086 discloses the quinolone compound having the following general formula C!: ##STR10## in which R and R.sub.1 independently of one another represent hydrogen or C.sub.1 -C.sub.5 alkyl;
Among the compounds C! disclosed in said European early patent publication the typical substituent on 7-position of quinolone nucleus is a group having the following structure: ##STR11##
However, the compound of formula C! does not include any compound having both oxime group and aminomethyl group on 7-position, and therefore, is different from the compound of the present invention.
The common characteristic feature of the known oxime or hydroxyamine-derived compounds as mentioned above is that they exhibit a good activity against gram-positive strains including MRSA (Methicillin Resistant Staphylococcus aureus) strains in comparison with the early developed quinolone compounds but show a weak activity against gram-negative strains in comparison with the antibacterial agents including ofloxacin or ciprofloxacin. Therefore, it can be said that their antibacterial spectrum may be narrower than that of the known ofloxacin or ciprofloxacin antibacterial compound.
Thus, on the basis of prior art as mentioned above the present inventors have extensively studied to develop the novel oxime-aminomethyl compound, which shows a potent antibacterial activity against broad spectrum pathogenic strains including resistant strains and also exhibits more improved pharmacokinetic properties and high absorption in living body, by introducing various substituted pyrrolidine groups into 7-position of quinoline nucleus and determining pharmacological activities of the resulting compounds. As a result, we have identified that the quinolone compounds having the general formula (I), as defined above, wherein 4-aminomethyl-3-(optionally substituted)oxime-pyrrolidine group is introduced into 7-position of quinoline nucleus can satisfy such purpose, and thus completed the present invention.
Therefore, it is an object of the present invention to provide a novel quinoline(naphthyridine) carboxylic acid derivative of formula (I), as defined above, which shows a potent antibacterial activity against broad pathogenic strains including both gram-positive and gram-negative strains and also has a good pharmacokinetic property.
It is another object of the present invention to provide a process for preparing the novel quinoline(naphthyridine) carboxylic acid derivative of formula (I).
It is a further object of the present invention to provide an antibacterial composition comprising the novel quinoline (naphthyridine)carboxylic acid derivative of formula (I) as an active component.